DYNA JOURNAL ENGINEERING

Many scientific works have been contributed to show that its use can contribute to a multitude of applications based on these characteristics, from paints and other construction materials to batteries, solar generation, electronics and telecommunications.

It was initially produced by the method of exfoliation of graphite at room temperature, as practiced by its discoverers, the 2010 Nobel Prize winners Andrei Geim and Konstantin Novosiolov, and others have followed, such as those of deposition from the vapor phase (CVD = Chemical Vapor Deposition), the solvent exfoliation (LPE = Liquid Phase Exfoliation) or exfoliation by oxidation of graphite and reduction of graphite oxide obtained: all of them from graphite, whose atomic structure is also hexagonal but with the layers overlapping they form molecules united by Van der Waals' forces, weaker than the inter-atomic ones. The difficulties and cost of these processes mean that small quantities of graphite are now available at high prices, limiting large-scale applications.

The novelty has been given by a recent article published in Nature (Gram-scale bottom-up flash graphene synthesis) by researchers from Rice University (Houston - Texas) who claim to have found a process that by rapid heating of cheap carbon sources, such as coal or wood, petroleum coke, carbon black or even organic waste, tires or plastics, can provide quantities of graphite on a gram scale in less than a second. The product, called graphite flash (FG) after the process used to produce it, shows a poorly ordered (turbostratic) arrangement between the stacked graphite layers. No furnace, solvents or reactive gases are used and yields depend on the carbon content of the source; with high contents, such as carbon black, coal or petroleum coke, yields can range from 80 to 90% and no purification measures are required.

The laboratory experiments have been carried out in tubes where an energy source is discharged between two electrodes that raise the temperature of the starting material to about 3,000ºK for 10 milliseconds. It is assured that the refinement of the process will allow in about two years to pass economically and safely from the current scale of grams to produce 1 kg of graphite powder per day.